Glomerella cingulata

Systematic position and nature of the pathogen: Glomerella cingulata is an ascomycete fungus belonging to the Phyllachoraceae family. In agricultural pathology, it is widely recognized by its asexual morph, Colletotrichum gloeosporioides. It is considered a broad-spectrum, polyphagous pathogen capable of infecting numerous agricultural and horticultural crops, representing a major challenge for food production worldwide.

Associated diseases and host range: This pathogen is the primary cause of anthracnose and bitter rot in a wide variety of plants. Common hosts include apples, pears, grapes, strawberries, avocados, and tropical fruit trees. The infection manifests as sunken lesions on fruits, leaves, and stems, which often develop characteristic acervuli (spore-producing structures). These lesions lead to tissue maceration and fruit rot, making the produce unsuitable for the market.

Biology and life cycle: The life cycle involves both sexual (ascospore) and asexual (conidial) stages. The fungus overwinters as mycelium or ascospores in mummified fruit, dead branches, and decaying plant debris. During the growing season, conidia are spread via splashing rain, irrigation water, and wind. The fungus exhibits a hemibiotrophic lifestyle, initially colonizing host tissue without causing damage, followed by a destructive necrotrophic phase.

Environmental conditions and impact: Disease development is heavily favored by warm temperatures (20–28°C) and high humidity or frequent rainfall. The pathogen is particularly devastating because it can infect fruits at an early stage, remaining latent until the fruit approaches maturity. This leads to substantial post-harvest losses, as seemingly healthy produce begins to rot shortly after harvesting or during transit.

Protection and control measures: Effective management of Glomerella cingulata requires a multifaceted approach:

• Sanitation: removal and destruction of infected twigs and mummified fruit from the orchard.
• Pruning: maintaining optimal canopy architecture to improve airflow and reduce humidity.
• Fungicide applications: preventative use of contact and systemic fungicides, particularly during bloom and fruit set.
• Post-harvest: prompt cooling and storage management to inhibit latent infection growth.